09 Prius Randomly total loss of memory and restart when turn off car

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Cheffaz, Nov 30, 2021.

  1. Cheffaz

    Cheffaz Junior Member

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    09 Prius Randomly total loss of memory and restart when turn off car.

    only happens when you turn off the car. not when driving.

    HV battery? Inverter? any ideas would be helpful.

    Thanks
     
  2. jerrymildred

    jerrymildred Senior Member

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    What leads to this conclusion? I'm thinking: drives rough, bad fuel economy, clock reset, radio presets gone, phonebook wiped, etc.

    At any rate, the traction battery and inverter would have no effect on anything like that. But a loose connection on the 12v might do some weird things. If you tell us what you observe, it would be helpful.
     
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Everything about this screams 12v battery or 12v battery connections..........
     
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  4. Cheffaz

    Cheffaz Junior Member

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    I will check the battery connections later today. Thanks!
     
  5. bisco

    bisco cookie crumbler

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    be sure to check negative connection to body
     
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  6. edthefox5

    edthefox5 Senior Member

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    A healthy 12 volt battery in this car lives at around 12.6 volts.

    When testing 12 volt battery condition always use the front jump point. It does not matter what it measures at the battery only matters what’s hitting the front fuse box.

    If your battery is over 5 years old and has been sitting a lot from covid
    Just replace it. In the reinstallation you may discover the loose connections.
    Plus you can clean all the water out of the battery hole.
     
  7. Cheffaz

    Cheffaz Junior Member

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    All connections are now tight and one seemed loose, and it hasn't happened since tightening. this may have fixed the problem, i will report back in a few days...
     
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  8. bisco

    bisco cookie crumbler

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    thanks! i hope that is it.
     
  9. Cheffaz

    Cheffaz Junior Member

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    funny thing it happened once again yesterday but who knows.... could it be the hv battery dying its the original battery and I have a new optima yellow top so i know its not that
     
  10. ChapmanF

    ChapmanF Senior Member

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    Nope, that was ruled out when you said this:

    So your issue only happens at times when the traction battery is out of the picture.
     
  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    You could test it, or have it tested. It's a little more advanced than just a voltage test; not sure of the best term to search would be, maybe electronic automotive load tester. I use a Solar BA5, current model is BA9. Ancel comes up a lot, on Amazon. A lot of automotive retailers selling batteries will have a pro-level tester, and be willing to test for free.
     
  12. Cheffaz

    Cheffaz Junior Member

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    Yes when I shutdown it will randomly turn on with memory loss
     
  13. jerrymildred

    jerrymildred Senior Member

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    Unless you actually test it, you're just assuming that's not it; you don't know it. New batteries have been known to not be charged up or even be defective. But by now, unless it's defective, normal driving should have brought it up to a normal charge. But I'd still check it if it was mine.
     
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